The present invention relates to a body for radiating far-infrared radiation. More specifically, the present invention relates to a body for radiating far-infrared radiation in which a SiC ceramic is employed, to a drying apparatus including the body, and to a firing apparatus including the body.
Far-infrared radiation possesses small reflection and transmission of energy since far-infrared radiation has almost the same range of wave lengths as the wave lengths which water, an organic matter, a human body, and the like can absorb. Therefore, far-infrared radiation can transfer energy efficiently to such subjects. Further, far-infrared radiation raises the temperatures of the inner portion and the outer portion of such a subject almost simultaneously because resonance is caused by the correspondence of the above-mentioned wave length and heat is generated inside the subject since far-infrared radiation is transferred up to the deep portion of an organic matter and the like. For such reasons, extensive research has recently been made into far-infrared radiation.
Far-infrared radiation can be widely applied to various kinds of heat treatment such as drying, heating, roasting, fermentation, ripening, and heat insulation. For example, it can be used for not only predrying plastics, drying spot coating, a fish oven having continuous system, roasting coffee, fermenting tea, heating food such as pancakes and meat, but also devices for medical treatment by irradiation with far-infrared radiation.
It is most preferable for the body to radiate far-infrared radiation having a frequency corresponding to the frequency which the subject to be treated possesses in view of the efficiency of the energy. However, it is inappropriate, in view of industrial costs, for producing individually each ceramic for radiating far-infrared radiation, having a frequency corresponding to an inherent frequency of each of the subjects to be treated.
Therefore, extensive research has been made into materials having high emissivity in a wide range corresponding to all the wave lengths which far-infrared radiation possesses so as to be used as a material for a body for radiating far-infrared radiation. As ceramic materials, alumina and cordierite are well known.
However, the above-described ceramic materials are still not satisfactory, and the emissivity of such a material has room for further improvement.
Moreover, a body for radiating far-infrared radiation is often exposed to various kinds of chemical substances during heat treatment, and there has been some problems regarding the anticorrosivity against these chemical substances.
Further, it is required that the material itself possesses high strength so as to avoid breakage during handling.